In this particular extract from A Room of One's Own, Woolf wonders what would've happened had Shakespeare had a sister, equal to him in genius and only different from him in terms of gender.
The conclusion she draws from this thought experiment is pretty bleak, to say the least. From an early age, the young lady has her genius stifled by an unappreciative family who order her to mind the stew or mend stockings instead of bothering herself with books and papers. Unlike her brother, who's been encouraged to read the great writers of ancient literature such as Horace and Virgil, she receives no formal education, in common with the standards of the time.
Before long, the young lady has been betrothed—against her will—to the son of a neighboring wool stapler. But Shakespeare's sister is not prepared to submit to her father's wishes. So she escapes to London, where she hangs around stage doors in the hope of being discovered as an actress. Yet this proves to be a soul-destroying experience, as no one takes her seriously. Everyone just laughs in her face.
A stage manager takes pity on her, but proceeds to take advantage of her and gets her pregnant. In a fit of despair, Shakespeare's sister kills herself one cold winter's night. The young woman had a poet's heart, meaning that it was full of "heat and violence" (that is to say, passion). But because this heart was trapped inside the body of a woman, and because innate genius of talented women such as herself wasn't recognized by society, there was nowhere for that passion to go. As it couldn't be expressed in poems or plays, it was turned instead to suicide. This tragic end represents a savage indictment on a society which all too often doesn't take women seriously as artists or creators.